(1) Field of the Invention
The present invention relates to a display device, and in particular, to a display device having a touch panel and a front window on the front side of the display panel.
(2) Description of the Related Art
Various types of display devices, such as liquid crystal modules (liquid crystal display devices) and organic electroluminescent display devices, are used for many portable information apparatuses, such as cellular phones, personal digital assistants (PDAs), digital cameras and multimedia players.
In recent years, the display device of various types of apparatuses has been provided with a touch panel on the front surface of the display panel as an input apparatus for these. In addition, a front window has also been provided in order to protect the touch panel and the display panel. JP2011-048055A discloses the structure where a touch panel and a front window are provided on the front surface of a liquid crystal display device.
FIGS. 1 to 4 are diagrams showing the prior art for illustrating a state where a capacitive touch panel and a front window are connected together. FIG. 1 shows a state where a flexible printed circuit 2 is connected to a capacitive touch panel 1. FIG. 1 shows the front surface side of the touch panel 1, and a wire pattern, not shown, is provided on a film formed on the surface of the touch panel. A flexible printed circuit is usually connected to the touch panel 1 on the same surface as that on which a film is formed.
As shown in FIG. 2, a group of electronic parts, including a control IC (file), is mounted on the flexible printed circuit 2. Therefore, as a general specification, a reinforcing plate 3 made of polyimide or the like is provided on the rear surface of the board where the electronic parts are mounted. FIG. 2 is a diagram showing the touch panel 1 as viewed from the rear. A terminal portion 4 for interface is provided at one end of the flexible printed circuit 2.
FIG. 3 shows a state where a front window 6 is mounted on and pasted to the touch panel 1 in FIG. 1 on the front surface side with an adhesive layer in between. FIG. 4 is a cross-sectional diagram along one-dot chain line A-A′. The base of the touch panel 1 is made of glass, and thus has high physical strength and low flexibility. Therefore, it is necessary for the adhesive layer 7 to be thicker than the flexible printed circuit 2.